The Jews ordained and took it upon themselves and their descendants and all who joined them that without fail every year they would keep these two days at the appointed time and as it was written, That these days should be remembered (imprinted on their minds) and kept throughout every generation in every family, province, and city, and that these days of Purim should never cease from among the Jews, nor the commemoration of them cease among their descendants.

And Mordecai recorded these things, and he sent letters to all the Jews who were in all the provinces of the King Ahasuerus, both near and far, To command them to keep the fourteenth day of the month of Adar and also the fifteenth, yearly, As the days on which the Jews got rest from their enemies, and as the month which was turned for them from sorrow to gladness and from mourning into a holiday -- "that they should make them days of feasting and gladness, days of sending choice portions to one another and gifts to the poor. read more.
So the Jews undertook to do as they had begun and as Mordecai had written to them -- " Because Haman son of Hammedatha, the Agagite, the enemy of all the Jews, had plotted against the Jews to destroy them and had cast Pur, that is, the lot, [to find a lucky day] to crush and consume and destroy them. But when Esther brought the matter before the king, he commanded in writing that Haman's wicked scheme which he had devised against the Jews should return upon his own head, and that he and his sons should be hanged on the gallows. Therefore they called these days Purim, after the name Pur [lot]. Therefore, because of all that was in this letter and what they had faced in this matter and what had happened to them, The Jews ordained and took it upon themselves and their descendants and all who joined them that without fail every year they would keep these two days at the appointed time and as it was written, That these days should be remembered (imprinted on their minds) and kept throughout every generation in every family, province, and city, and that these days of Purim should never cease from among the Jews, nor the commemoration of them cease among their descendants. Then Queen Esther, the daughter of Abihail, with Mordecai the Jew, gave full power [written authority], confirming this second letter about Purim. And letters were sent to all the Jews, to the 127 provinces of the kingdom of Ahasuerus, in words of peace and truth, To confirm that these days of Purim should be observed at their appointed times, as Mordecai the Jew and Queen Esther had commanded [the Jews], and as they had ordained for themselves and for their descendants in the matter of their fasts and their lamenting. And the command of Esther confirmed these observances of Purim, and it was written in the book.